The effects of negative toe in practice
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From: Melbourne, VIC, Australia
The effects of negative toe in practice
I recently went to get an alingment after putting coilovers back on as a part of a process of elimination for recent handling issues.
The alingment shows the left and right wheels to all be within 0.2mm of each other, so I don't think there are any bent parts or anything.
The front toe was at -8.6 each side and was corrected by the aligner to 0/0.
The rear toe was at -8.9mm Left and -8.7mm Right and could not be adjusted any further towards neutral toe as the compensator arms are adjusted fully towards the centreline of the car.
I assembled a ghetto alignment measuring device (the well documented string technique) and for the front it showed exactly as I expected, the manufacturer wheel base width from each side of the front set of wheels. So the string tells the truth so far.
HOWEVER, the string told me that the difference between the front and back of the centre of each rear wheel was 45mm total toe out!!!! If the aligner is right, it's still nearly -18mm total toe, if the string is right, it's -22.5mm per side!
<U>What effect would such extreme toe out have on a front wheel drive with hard suspension?</U>
The alingment shows the left and right wheels to all be within 0.2mm of each other, so I don't think there are any bent parts or anything.
The front toe was at -8.6 each side and was corrected by the aligner to 0/0.
The rear toe was at -8.9mm Left and -8.7mm Right and could not be adjusted any further towards neutral toe as the compensator arms are adjusted fully towards the centreline of the car.
I assembled a ghetto alignment measuring device (the well documented string technique) and for the front it showed exactly as I expected, the manufacturer wheel base width from each side of the front set of wheels. So the string tells the truth so far.
HOWEVER, the string told me that the difference between the front and back of the centre of each rear wheel was 45mm total toe out!!!! If the aligner is right, it's still nearly -18mm total toe, if the string is right, it's -22.5mm per side!
<U>What effect would such extreme toe out have on a front wheel drive with hard suspension?</U>
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Joined: Feb 2006
Posts: 189
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From: Ontario, Canada
Re: The effects of negative toe in practice (Dylanamus)
Excessive tire wear, increased rolling drag, twitchy/unstable turn-in.
Make sure you have the strings set-up parallel to each other by measuring the distance between the strings in front and behind the car. Track width differences can throw your measurements off that way.
That is alot of toe either way you look at it. 1mm of toe is about 0.1* so it should be noticable to the eye if it is out by that much (2.3* of toe out per side!)
Modified by bsclywilly at 7:35 AM 4/4/2008
Make sure you have the strings set-up parallel to each other by measuring the distance between the strings in front and behind the car. Track width differences can throw your measurements off that way.
That is alot of toe either way you look at it. 1mm of toe is about 0.1* so it should be noticable to the eye if it is out by that much (2.3* of toe out per side!)
Modified by bsclywilly at 7:35 AM 4/4/2008
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From: Melbourne, VIC, Australia
Re: The effects of negative toe in practice (bsclywilly)
I calculated using the radius of the wheel+tyre that every 5mm is 1 degree.
My camber is set at -1.5 degrees and you can sure see that with the naked eye. Toe plays more tricks with your mind due to the angles of side skirts and things like that that don't necessarily refelct the angles of the centreline. That said, yes, you can definitely see that there's positive toe and many people have commented on it.
I've practically rebuild the suspension, brakes and steering so far, so I'm really crossing my fingers that this is it. I get some pretty bad wandering under heavy acceleration or braking and it just doesn't feel safe at all to even feather the brakes when riding a corner (I usually avoid braking on corners anyway, but sometimes if there are two apices, the second sharper than the first, then you really have no choice).
My camber is set at -1.5 degrees and you can sure see that with the naked eye. Toe plays more tricks with your mind due to the angles of side skirts and things like that that don't necessarily refelct the angles of the centreline. That said, yes, you can definitely see that there's positive toe and many people have commented on it.
I've practically rebuild the suspension, brakes and steering so far, so I'm really crossing my fingers that this is it. I get some pretty bad wandering under heavy acceleration or braking and it just doesn't feel safe at all to even feather the brakes when riding a corner (I usually avoid braking on corners anyway, but sometimes if there are two apices, the second sharper than the first, then you really have no choice).
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